As electric vehicles (EVs) become more mainstream, the infrastructure that powers them is evolving rapidly. Behind the scenes of every public EV charger is a smart communication layer that ensures chargers operate efficiently, securely, and interoperably. That communication standard is called OCPP — Open Charge Point Protocol.

In this article, we’ll break down what OCPP is, why it matters, how it works, and the different versions available today. Whether you’re an EV driver, charging network operator, or tech enthusiast, this guide will help you understand how OCPP is shaping the future of electric mobility.

🔌 What is OCPP?

OCPP (Open Charge Point Protocol) is an application protocol used to enable communication between Electric Vehicle Supply Equipment (EVSE)—commonly known as EV chargers—and a Central Management System (CMS), often referred to as a Charge Point Operator (CPO) backend.

It is vendor-neutral and open-source, developed by the Open Charge Alliance (OCA) to standardize how EV chargers and management systems talk to each other.

Think of OCPP as the universal “language” between the charging station and the software that manages it.

⚙️ How OCPP Works

OCPP defines a set of WebSocket-based or SOAP-based messages that are exchanged between the client (charge point) and the server (backend system).

For example:

  • When a driver plugs in their EV, the charger sends a StartTransaction message to the backend.
  • The backend authenticates the session and sends a StartTransactionConfirmation.
  • Once charging ends, the charger sends a StopTransaction message.

Other key message types include:

  • Heartbeat: to ensure the charger is online
  • StatusNotification: to report charger availability
  • BootNotification: sent when the charger powers up
  • MeterValues: for usage data and billing
  • FirmwareUpdate, Diagnostics, and RemoteStart/Stop commands

These interactions enable remote control, monitoring, diagnostics, and software updates — all of which are essential for smart charging infrastructure.

🚀 Why is OCPP Important?

  • Interoperability: OCPP allows chargers from different manufacturers to connect to any compliant backend, reducing vendor lock-in.
  • Scalability: Operators can manage thousands of chargers efficiently using a single system.
  • Smart Charging: OCPP supports load balancing, grid integration, and energy optimization.
  • Security: Latest versions support enhanced encryption, authentication, and access control mechanisms.

OCPP is especially important for public EV charging networks, fleet operators, municipalities, and utility companies that require flexibility and operational efficiency.

🔢 OCPP Versions Explained

Over the years, OCPP has evolved to meet the growing demands of EV infrastructure. Here’s a look at its major versions:

✅ OCPP 1.2 (2009)

  • The first version
  • Limited functionality
  • Largely outdated and no longer used

✅ OCPP 1.5

  • Improved stability
  • Better message structure
  • Still lacks advanced features

✅ OCPP 1.6 (2015)

  • Most widely deployed version
  • Supports JSON over WebSocket and SOAP
  • Adds:
    • Remote Start/Stop
    • Smart Charging (Load Profiles)
    • Firmware Management
    • Diagnostics
  • Still supported by most major networks today

✅ OCPP 2.0 (2018)

  • Major overhaul of the protocol
  • Adds:
    • Device Management
    • Security Profiles
    • ISO 15118 integration (Plug & Charge)
    • Improved Smart Charging
    • Better data modeling

✅ OCPP 2.0.1 (2020)

  • The latest and stable version
  • Focused on bug fixes and practical enhancements from real-world implementations
  • Growing adoption in next-generation networks

📝 Note: OCPP 2.x is not backward compatible with 1.6, but many platforms support dual-stack operation.

🛠️ Technical Architecture Overview

A typical OCPP-based EV charging setup consists of:

  1. Charge Point (Client):
    • Hardware installed at EV charging stations
    • Acts as the OCPP client
    • Initiates communication
  2. Central System (Server):
    • Backend system that processes OCPP messages
    • Manages user sessions, pricing, diagnostics, and energy usage
  3. Communication Layer:
    • Typically uses WebSockets over TLS for secure, real-time, full-duplex communication
    • Some older implementations use SOAP over HTTP
  4. Optional Add-ons:
    • Token authentication (RFID, app-based)
    • OCPI/OSCP/ISO 15118 integration for roaming and advanced smart grid features

🔒 Security in OCPP

Starting with OCPP 2.0, the protocol includes support for secure communication profiles, including:

  • TLS Encryption
  • Client-side and server-side certificates
  • Secure firmware updates
  • Signed metering and transaction data

These features make OCPP ready for enterprise-scale, mission-critical deployments.

🌍 Real-World Use Cases

  • Public Charging Networks: Roaming across different charger brands
  • Fleet Management: Real-time diagnostics and energy consumption tracking
  • Retail Sites & Fuel Stations: Revenue tracking and load optimization
  • Smart Cities & Utilities: Demand response and grid integration

📈 Final Thoughts

OCPP is the backbone of modern EV charging infrastructure. As the electric vehicle ecosystem expands, having a universal, open, and future-ready protocol like OCPP ensures that EV charging remains reliable, scalable, and secure.

Whether you’re deploying 5 chargers in a parking lot or 5,000 across a city, OCPP gives you the flexibility to choose the hardware and software that suit your needs — all while ensuring interoperability with the rest of the EV ecosystem.

Want to learn more about OCPP, EV charging, or smart infrastructure? Follow this blog for future deep-dives, comparisons, and real-world implementation guides!